We all know we ought to check our tyres regularly, both for wear and tear, and the tyre pressures, but do you really know what you are looking for? Your car tyres are the only part of your car that is in contact with the road, so the way your car drives will depend a lot on the condition of your tyres. The area of each tyre that is actually in contact with the road surface is only about the size of a foot, so if you want to stop when you press your brake to the floor, you need that small area of tyre to have sufficient tread and the right tyre pressure to stop in adequate time. After all, under an emergency braking situation, it could save your life.

So you are ready to check your tyres. Here is a quick list of things you should be looking out for:

The tread wear indicator bar - this is a bar going across the treads that is only visible when the tyres are wearing out. There will be a few of them in different places, and if your treads are at the same level as the indicator bars, you probably have only 2 millimetres of tread left. As the legal limit is 1.6 millimetres, this means it is time to book in for your tyres to be replaced.

Tread depth - if you aren't sure about your indicator bars, or think you have been driving on them for a while and need to check if your tyres are still legal, then you need to check your tread depth more accurately. Ideally you should use a tread depth gauge, as this will tell you exactly how much wear is left, but in a pinch you can use a 20 pence piece. Just push it in between the treads and if you can see the band around the outside, your tyre needs replacing. Always check tread depth in a few places around the tyre.

Sidewall - it isn't just the surface of the tyres you need to check, you should also check for any cracks or damage to the sidewalls. If you can see any grooves that shouldn't be there, your tyre could be developing a leak. While this may just be a slow leak, it could blow out while you are driving, which is likely to cause an accident. Better to get your tyres replaced before that happens.

Bulges - finally you should do an overall inspection of each tyre. Anything unusual on the surface of the tyre such as bulges are a sign that there is damage somewhere under the surface of the tyre. This one is urgent; if you find a bulge, get your tyres changed straight away.

You should aim to carry out this check at least every month, and it is also worth checking your car Mot Harlow before any long journeys, particularly if you are going to be further from a garage than you usually are. The rest of the time, you can still keep an 'eye' on your tyres from inside the car - if you feel any excessive vibration, one possible cause is your tyres, so they should be the first thing you check. Even if something else is causing the vibration, if you don't rectify the problem sooner rather than later, your tyres could end up paying the price of the uneven driving.